Treatment of textile fibers for bleaching purposes.



es. 083 lii@ll@l@ll@@ UNITED sT 'rEs Pa'rENTj OFFICE.

EMILE THEODORE JOSEPH WATREMEZ, OF BRUSSELS, BELGIUM.

' TREATMENT OF TEXTILE FIBERS FOR BLEACHING PURPOSES.

To all whom, it may concern:

Be it known that I, EMILE 'lI-raononn Jo- SEPH VVATREMEZ, a citizen of the Republicof France, and resident of Brussels, Belgium, have invented a new and useful Treatment of Textile Fibers for Bleaching Purposes, which is fully set'forth in the following specification.

This invention relates to an improved process for the preparation of textile fibers of vegetable origin, more particularly, but not exclusively, applicableto fibers difficult to bleach, of which flax is a typical example.

The improved process chiefly consists in treating the natural coloring matters of the fiber with metal salts, the corresponding oxids of which are little, or not at all, soluble in water Salts containing as the single metal an alkaline metal, are therefore. excluded, apart from the cases where it is necessary to produce an alkaline medium. The treatment of the fiber eliminates to a great.

extent the natural coloring matters, and renders easily destructible by the bleaching agents those which are not eliminated; it

comprises the following steps:

I. Boiling.This operation must be car- I ried out in an alkaline medium; the treatment is by a salt of a metal,--the oxid of which is soluble in an excess of-alkali, such as zinc in the form of zinkate of soda, chromium in the form .of chromate of potash, tin' in the form of stannate of soda, and preferably aluminium in the form of aluminate of soda; it is important that the excess of alkali should be always'sufiicient for insuring complete solution of the metal oxid.

The proportions vary of course with the nature of the fibers to be treated, but nevertheless by way of example the following composition of a boiling bath of 1000 liters may be mentioned: 10 kg. of crystallized alum and 5 kg. of carbonate of soda are dissolved together, and when this operation is completed, the precipitate, which is formed at' such time, is dissolved in 20 liters of caustic soda lye at 3236 Baum, and the necessary water is added, the use of the carbonateof soda enabling a smaller quantity of causduced and heated. Discoloration quickly beginslong before the boiling temperatureis reached. The boiling is continued for about two hours, and the material treated is preferably left to cool in the bath used for'boilcoloring matter is eliminated, and the colormg matters still left, are in combination with the metal. If the oxid of the said metal is colorless, and if the fibers treated are easy to bleach, the bleaching operation can be at once proceeded with.

2. Attack of metal salts ezm'stz'ng in the fiber after the first operation-These metal salts are treated with oneor more agents capable of destroying or modifying them. Ac-

cording to the metal or metals utilized for boiling, the treatment is effected with a suitable acid, the concentration of the acid varying according as the operation is car-' rled out hot or cold. As regards alumina eearta Specification of Letters Patent. Patented Mar. 30, 1915. l

. Application filed February 6, 1914. Serial No. 817,060.

good results are obtained by means ofsulfuric acid at the rate of 2 or 3-per thousand.

The treatment could also be effected by means of other substances, such as alkaline sulfids; in such case it is advisable to destroy, by means of anacid, sulfur compounds which have been produced in the fiber.

Generally speaking, this treatment is sufficient forobtaining perfect whiteness in a few hours at the outside when followed by passage throughan ordinary chlorin bath of medium or weak strength. Nevertheless, for

certain fibers or certain fabrics specially difficult to bleach, a second treatment with a metallic salt solution is madeuse of; that is to say, before proceeding to bleaching, the natural coloring matters remaining are again treated with a metal salt, after removal of the metal utilized in the first'operation. For example, it is convenient to employ a solution of bisulfite of soda, of 06-12% mixedwith 2-4 per thousand of hydrochloriciacid containing in solution a metal such as copper, chromium or manganese. The whole is then rinsed with cold water, and passed through a chlorin bath as before.

It must be pointed out that if the fiber is treated with a copper or chromium salt, a beautiful bluish-white is obtained, the blue tints disappearing easily under the action of any substance such as nitric acid, capable of dissolving the corresponding oxids. If manganese is used for treatment, the fiber remains colored yellow, the action of the chlorin bath is continued until the said tint is thoroughly uniform when viewed by transmitted light, and manganese oxid is remoged, for instance, by means of sulfurous aci The process described has the advantage of being very economical, as the various manipulations are reduced to a minimum, the raw materials are very cheap and the treat ment quick. A very pure white is obtained, and the loss in weight of the fabric is insig' nificant, for only the natural coloring materials of the fiber are attacked, and not their support, that is to say, cellulose, the latter being absolutely or almost absolutely intact.

Claims.

l. The herein-described process of treat ing textile fibers of vegetable origin previous to bleaching, which consists in subjecting the fibers to the action of an alkaline bath containing the salt of a metal, the oXid of which is soluble in the excess of alkali of the bath, to attack the vegetable coloring matter and in destroying the metal salts remaining in the fibers.

2. The hereindescribed process of treating textile fibers of vegetable origin previous to bleaching, which consists in subjecting the fibers to the action of an alkaline bath containing the salt of a metal, the oxid ofwhichis soluble in the excess of alkali of the bath, to attack the vegetable coloring matter, and in treating the said fibers with an acid of a concentration varying with the temperature of the bath to destroy the metal salts remaining therein.

The herein-described process of treating textile fibers of vegetable origin previous to bleaching, which consists in subjecting the fibers to the action of an alkaline bath containing the salt of a metal, the oxid of which is soluble in the excess of alkali of the bath, to attack the vegetable coloring matter, and in successively treating the fibers with alkaline sulfids and with an acid of concentration varying in accordance with the temperature of the bath to destroy the metal salts remaining therein.

4. The herein-described process of treating textile fibers of vegetable origin pre vious to the bleaching, which consists in subjecting the fibers to the action of an alkaline bath containing the salt of a metal, the oXid of which is soluble in the excess of alkali of the bath, to attack the vegetable coloring matter, in destroying the metal salts remaining in the fibers, and in again subjecting the fibers to the action of the first-mentioned bath containing the said metal salt, the oXid of which is soluble in an excess of alkali.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

EMILE THEODORE JOSEPH WATREMEZ.

Witnesses CHARLES O. JOHNSON, EMILE VON WANSALS. 

